Dry shaver cutter head



Sept. 16, 194 A. s. KNAPP 2,256,029

DRY SHAVER CUTTER HEAD Filed Feb. 21, 1938 INVENTOR.

ATTORNEY 5 Patented Sept. 16, 1941 UNITED STATES PATEN OFFlCE DRY SHAVER CUTTER HEAD Andrew S. Knapp, St..L0uis, Ma, assignor to Knapp-Monarch Company, St. Louis, M0., a corporation of, Missouri Application February 21, 1938, Serial No. 191,699 3 Claims. (CI. 30-43) An object of my invention is to provide a dry shaver cutter head which can be formed inexpensively of sheet metal, the outer cutter member being provided with slots whereby to form between the slots outer cutter teeth with which 1 an inner cutter member shearingly cooperates.

Another object is to provide the slots in the outer cutter member in two series along opposite sides of the longitudinal center thereof, the slots terminating spaced from each other along the center and the slots in one series being wider than the slots in the other series, the relative widths being such that the slots on one side of the cutter head are adaptable to receive only relatively fine hair while those on the other side are adaptable to receive relatively coarse hair.

A further object is to provide between the spaced series of slots a reinforcing and separating rib formed by depressing the sheet metal forming the outer cutter member, which rib separates one series of the slots from the other series thereof and reinforces. the center of the outer cutter from bending inwardly when pressed against the face of the user.

Still a further object is cutter of the character described which is adaptable fcr efficiently cutting either a days growth ofbeard or a longer growth of beard, the narrow slots being adaptable to receive the relatively fine. hair resultant from a days growth of beard, whereas they are of insufficient width to receive hair of greater diameter such as produced by greater than a days growth, the wider slots being adaptable to receive hair of greater diameter thus making for close shaving of fine hair as well as for close shaving of relatively coarse hair.

With these and other objects in view, my invention consists in the construction, arrangement and combination of the various parts of my cutter head whereby the objects contemplated as well as other obvious objects are attained, as hereinafter more fully set forth, illustrated in the accompanying drawing, and covered in the appended claims. I

With reference to the drawing: v

Figure 1 is a sectional view through a dry shaver showing my improved form of cutter head mounted therein for use, the parts being shown on an enlarged scale, the section being taken substantially through the centerfrom end to end of the cutter head.

Figure 2 is a similar sectional view of the cutter head only, the section being taken at a point spaced on either side of the center thereof.

to provide an outer 2,;

the cutter head readily adaptable Figure 3 is a bottom plan view as looking upwardly at Figure 2, parts of the outer cutter being broken away to show the inner cutter.

Figure 4 is an enlarged sectional view on the line 4--4 of Figure 2 with the right side of the cutter head in Figure 2 transposed to the left side in Figure 4 to place the slots in each side of the cutter adjacent each other and thereby facilitate comparison between the widths of the slots in opposite sides of the outer cutter.

Figure 5 is an enlarged sectional view on the line 55 of Figure 2 showing the relative relationship between the cutting teeth of the inner and outer cutter; and

Figure 6 is a similar sectional View on the line 6-6 of Figure 2 with the parts turned upside down to better illustrate the comparison between the slots on opposite sides of the center of the outer cutter as shown adjacent each other in Figures 5 and 6.

On the accompanying drawing I have used the reference character C to indicate generally a casing of a dry shaver of the usual type having an electric motor (not shown) mounted therein for operating the shaver. A head member ii) is mounted in the top of the casing C and has a slot 12 to receive my cutter head assembly. The cutter head assembly includes an outer cutter member l3 which is preferably formed of relatively thin sheet metal. The outer cutter 13 has a pair of sides 13a and a cross member lab connecting the lower edges of the sides together. The outer cutter also includes reinforcing plates l4 and spacer blocks [5, all of which are held in assembled relation by countersunk rivets It. The plates M are grooved as at H to receive the head of a retainer spring l8 which normally retains the cutter assembly in position in the slot l2.

Within the cutter l3 an inner cutter I9 is provided. The inner cutter l9 has a slot 2! adapted to receive the upper end of an oscillating arm 2 l. The arm 2! is mounted for oscillation on a shouldered pivot screw 22 and driven in the usual manner from the motor in the casing C.

For retaining the inner cutter ill in shearing engagement with the outer cutter, a pair of spring-pressed rods 23 are provided. These have heads 24 engaging the cutter l9 and springs 25 urge them in the desired direction. The rods 23 are slidable in retainer nuts 28 and provided with heads 21 to prevent excessive extension of the heads 24 when the inner cutter is removed from the outer cutter.

The outer cutter has in one side a series of slots 28 and in the other side a series of slots rial of the cross member [371 between the slots.

28 and 29 thereof. The teeth 3| and 32, as clearly shown in Figure 2, terminate spaced from each other so as to receive between them the rib 30 without the rib interfering with the oscillating movement of the teeth.

As perhaps best shown in Figures 4, 5 and 6,

the slots 28 are narrower than the slots 29. The

relative width may be, for instance, .009 of an inch and .011 of an inch. I have found that a beard after a days growth consists of hairs which are somewhat less than .009 of an inch in diameter as illustrated at H and which can therefore be readily received in the slots 28, whereas a beard of more than a days growth consists of hairs which are somewhat larger in diameter as illustrated at H and which are not so readily receivable in the slots 28. The slots 29, however, being wider will readily receive the hairs H.

- It has been found by experiment that the slots of an outer cutter of a dry shaver should be as narrow as possible to operate the shaver with 'maximum efficiency. Accordingly, by providing both the narrow slots 28 and the wide slots 29 it is possible to use the side of the cutter having the slots 28 for the relatively fine hair of a days growth of beard while the slots 29 can be used when there is a greater period of time between shaves and the hairs therefore consequently become larger in diameter adjacent the skin. Thus, in a single cutter head I make provision for cutting'of fine hair as well as coarse hair and in either case a close shave can be secured as the cross member l3b can be made relatively thin.

Even when made thin, it is sufficiently reinforced against undesirable bending by the rib 3B which thereby serves as a strengthening member for the teeth of the outer cutter and as a separator between the spaced series of slots 28 and 29. During the manufacturing process this rib 30 serves as isolating means between the slots which. as illustrated in Figure 2, are cut across from the base of the rib, through the portion of the cross member I32) from the rib to its outer edge and then into the adjacent side l3a of the outer cutter.

While I have referred to'fine and coarse hair, it will be understood that I am only speaking generally of the same,long and short hair have different characteristics and in some cases it is easier to shave dry with one side of my shaver than the other. I have actually used my'shaver and I find'that it meets conditions that up to the present time have not been solved in dry shaving. My shaver may conveniently be used on either side during one shaving operation, thereby using the larger slots at the start of the shave and the finer slots at the finish of the shave.

The center reinforcing rib 38 not only serves to retain the cutter head or shearing plate in proper position at all times, but also separates the cutter head into separate shaving surfaces, so that two shaving surfaces can be used with a single inner cutter member. It will be noted that the teeth with a space therebetween into which the rib 30 partially projects, all of which makes for a compact unit.

The outer cutter head or member is of light Weight material properly reinforced of its own material by virtue of the reinforcing center rib which in no way interferes with the operation of the inner cutter.

Various changes may be made in the construction and arrangement of the parts of my dry shaver cutter head without however, departing from the real spirit and purpose of my invention. My intention, therefore, is to cover by my claims, such modified forms of structure or use of mechanical equivalent as may be reasonably included within the scope thereof.

I claim as my invention:

1. In a dry shaver cutter head, an outer cutter member of uniform thickness having a cutting face portion, said portion having a plurality of series of slots extending partially across the width thereof and defining thereby a plurality of cutting teeth in each of said series, an inner cutter member coacting with each of said series of cutting teeth, said slots being arranged on opposite sides of the center of said cutting face portion and being wider in one series than the slots in the other. series, and a relatively narrow imperforate separating and reinforcing rib on said cutting face between said series of slots forming an inwardly extending depression, said rib having a depth not greater substantially than the thickness of said inner cutter member, said rib being adapted to sustain the teeth on said cutting face against bending, under the pressure produced by normal shaving operations.

2. In a cutter head, an outer cutter member having a pair of supporting side Walls, a cross member connecting said side walls together and a reinforcing head at the ends of said side walls and cross member, said cross member on one side of the center thereof having a series of teeth and on the other side of said center having another series of teeth, the teeth of one of said series being spaced a greater distance apart from each other than the teeth of the other series with the ends of the teeth of one series in spaced relation with the corresponding ends of the teeth in said other series along the center of the outer cutter member, means along said center to prevent bending of the cross member when pressed against the users face comprising a depressed imperforate rib extending between the reinforcing beads at opposite ends of the cross member, and an inner cutter member having teeth coacting with the teeth of the outer cutter member, the teeth of said inner cutter member being formed in two series spaced from each other along the center of the inner cutter so that oppositely disposed ends of the teeth accommodate said rib in the space between them.

3. In a dry shaver cutter head, an outer cutter member of uniform thickness having a cutting face portion, said portion having a plurality of series of slots extending partially across the width thereof and. defining thereby a plurality of cutting teeth in each of said series, an inner cutter member having. elements, one at each side, of relatively thin cross section extending along the sides of said outer member and across the cutting face portion thereof and forming a series of inner cutting teeth on each side, one said series-of inner cutting teeth extending to a posiof my inner cutter project towards each other tion wherein the ends thereof are spaced along the center opposite the ends of said other series of inner teeth, the teeth on each side of said inner cutter member being adapted to coact with the respective series of cutting teeth in the outer cutting face portion, said outer teeth forming slots arranged on opposite sides of the center of said cutting face portion, the slots of one series being wider than the slots of the other series,

and a relatively narrow imperforate separating and reinforcing rib, formed on said cutting face between said series of slots forming a depression extending inwardly and between the ends of the cutting teeth of said inner cutter and sustaining the teeth on said outer cutting face against bending under the pressure produced by normal shaving operations.

ANDREW S. KNAPP. 

